Lenze DSD - Manual (Page 317)

Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
317
11 Drive Dimensioning
11.2 Motor selection
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11.2.5.1 Characteristic curves
Generally, DSD uses characteristic curves which apply to the respective selected rated voltage of the
supply system and to the standard configuration of the inverter.
The characteristic curves are represented in two classes:
• Characteristic curves in the Motor selection and Gearbox selection dimensioning step:
• Display what the motor is able to max. provide with the selected inverter family.
• Characteristic curves in the Inverter selection and Protocol dimensioning step:
• Display what the motor-inverter combination is able to max. provide in the selected operat-
ing mode (switching frequency, overload behaviour, control mode, mains choke).
For the calculation in DSD, the quadrant for operation in motor mode is reflected to the quadrant
for operation in generator mode and adapted if required. That way, it is ensured that the required
torque is provided independent of the selected electrical braking circuit.
If there is no characteristic available for the motor-inverter combination or the selected control
mode, DSD calculates a characteristic which is represented as a red dotted line.
By means of the motor characteristic the required torque of the application can be checked on the
basis of the max. available motor torque.
The following has to apply to each operating point M
M
= f(n):
[11-3] Check of the required application torque
The characteristic torque-speed curves of the motor-inverter combination presented in the DSD are
static characteristics. In the case of acceleration times ≤ 50 ms for servo inverters and ≤ 100 ms for
frequency inverters, the actual torque-speed behaviour may deviate considerably.
11.2.5.2 Continuous rated curves (S1 characteristics)
The continuous rated curve of a motor is affected by winding losses and core losses. Due to the core
losses increasing with the frequency, every motor has a continuous rated curve that decreases with
increasing speed.
• The winding losses are quadratically proportional to the current. Very high overloads therefore
result in a high increase of the losses. In order to consider both types of losses, the DSD uses a
thermal model of the machine.

Note!
If the standard configuration of the drive system has changed (e.g. use of a mains choke,
motor choke, long motor cables, or a "smooth" network), the actual characteristic can
differ considerably from the displayed one.
M
max,M
n ( ) M
max,App
n ( ) >